How to get nice green growth

My waterfall scrubber currently grows a nice crop of almost black dark green, some hair algae, but mostly stuff that comes off pretty easily when I scrape it. Sometimes with extra yellowish slime here and there.

It seems to work fine to reduce Nitrates and Phosphates, but I don't seem to get the hair algae lighter green growth that others seem to get.

The scrubber is two sided, with 30 watt red and blue LED lamps - with a pretty decent flow. The lamps are 3 inches from the screen on each side. Light cycle is 20 hours on, 4 off every day.

I get lots of algae, but not the luxuriant green growth I have seen in pictures here and on the other site.

the screen has been in use for at least 4 months at this point, I would call it mature.

For any plant to be nice and green ammonia is needed to some extent. The problem is- you should not want it in your tank at all for other well known reasons. I would say that not having bright green screen is actually good sign.

I would say that plants need nitrogen, and ammonia is just one form of that. But ammonia is released into the water either continuously by some corals or in bulk when a fish excretes waste. So while there should never be measurable ammonia, it is still there, it just gets consumed/converted very quickly.

Everytime I find dead snail in my tank , I also find nice green growth on the screen for several days to week.
After that growth returns to brownish yellow alien sort and keeps parameters at very low levels.
After 3 years of using scrubber I dont care about growth color anymore. Low N and P is what matters for me.